Perdita swenki is a species of bee in the family Andrenidae. It is found in North America. It is known to visit: Chrysopsis, Grindelia, Helianthus maximillianii, Liatris, Solidago juncea, and Solidago rigida.
References
Krombein, Karl V., Paul D. Hurd, Jr., David R. Smith, and B. D. Burks (1979), Catalog of Hymenoptera in America North of Mexico, vol. 2: Apocrita (Aculeata) https://www.biodiversitylibrary.org/item/26295#page/727/mode/1up